The present invention relates to the medical diagnostic imaging and minimally invasive stereotactic surgery arts. It finds particular application in conjunction with an integrated CT scanner and mechanical arm guided minimally invasive surgical tools and will be described with particular reference thereto. It is to be appreciated, however, that the invention is also applicable to guiding interventional surgical tools in conjunction with magnetic resonance imaging and other imaging systems capable of generating volumetric images. The system is also applicable to other surgical tools used in conjunction with real time imaging systems capable of monitoring a region of the patient during a minimally invasive surgical procedure.
Heretofore, several surgical instrument guidance devices have been proposed for use in conjunction with a CT scanner to allow a user to accurately place a catheter, drainage tube, or biopsy probe within a patient's body. U.S. Pat. No. 4,733,661 describes a hand held guidance device including a planar base with a bubble level to maintain the base in a horizontal position. Needle guides are provided on a support arm pivotally secured to the base, the guides slidingly supporting a catheter at a desired angle as the catheter into the patient's body. The guidance device includes a reference line formed upon the base adapted to be aligned with a transverse light beam projected by the CT scanner apparatus. Although it may be possible for the device to be used to accurately insert a biopsy needle within a patient's body without damage to any unintended targets, one major disadvantage of the device is its reliance upon an accurate human alignment between the reference line defined on the base of the device and the transverse light beam projected by the CT scanner. It would, therefore, be desirable to provide a surgical instrument guidance device which is not dependent upon a manual alignment step.
U.S. Pat. No. 4,583,538 proposes a free standing biopsy guide that is adapted to hold needles or probes at various selectable calculated angles. In using the device proposed in that patent, a reference point on the patient's body is found that exactly correlates to a point on the CT scan. This is accomplished by means of a localization device placed on the patient's skin which can be identified in cross section on the CT scan. Measurements of the localization device on the CT scan are then correlated to the device on the patient. The free standing biopsy guide is then adjusted according to those calculations. One disadvantage of the device taught by this patent is the time required to correlate the patient body reference point with selected points on the CT scan. In addition, certain inaccuracies may be introduced during the point correlation step and while adjusting the free standing guidance device. Accordingly, it would be desirable to provide a biopsy or other surgical instrument guide that is rigidly affixed to the CT scanner apparatus whereby precise and automatic correlation between the coordinate systems of the guidance device, patient table, and patient image volume are automatically established.
U.S. Pat. Nos. 5,628,327 and 4,651,732 propose various devices for supporting a laser apparatus for use in laser guided biopsies or other interventional procedures. However, neither of these apparatus provide for a combined laser and cannula guidance system. Further, neither of these teachings suggest an interchangeable surgical instrument guidance device.
The present invention provides a new and improved interchangeable surgical instrument guidance device and method for using same which overcomes the above-referenced problems and others.